The invention relates to a closure device for doors or the like, especially of motor vehicles, having a rotary latch which interacts with a pin for the locking of the door, a ratchet which arrests the rotary latch at least in the closed position of the door and which can be released with the aid of a release mechanism, and a motor-driven shutting aid, whereby the door can be pulled over the last part of its closing travel into the closed position.
Such closure devices are known, for example, for the tailgates of vehicles in which the gate only needs to be rested lightly against the bodywork and is then pulled into the closed position by the drive of the shutting aid. Such shutting aids may become problematical if, during the closing of a door or tailgate of a vehicle, activation of the shutting aid takes place although fingers or articles are still trapped between the gate and the frame. As a result there is a considerable risk of injury or risk of damage to the vehicle, the shutting aid and the trapped article, especially since in the case of known devices actuation of the release mechanism is also ineffective while the shutting aid is in operation. Even switching off the drive of the shutting aid fails to result in the desired opening of the door because the drives are usually of self-locking design, the door or gate merely being halted in its instantaneous position. Electronic detection of a trapped finger or article by evaluation of the load current of the drive motor is impossible because the increase in load is only slight.
The object of the invention is to provide a closure device for doors, hoods, gates and the like which reduces the risk of injury or risk of damage when the shutting aid engages.
The object is achieved, according to the invention, in that, when the release mechanism is actuated, the force flow between the drive of the shutting aid and the door to be closed is simultaneously mechanically interrupted.
With the aid of the closure device according to the invention it is possible, for the first time, by simple actuation of the release mechanism, not only to move the ratchet aside, as a result of which the rotary latch is released, but also to achieve an interruption of the force flow to the shutting aid and so to ensure free rotatability of the rotary latch, so that, even in the case of self-locking drives of the shutting aid, the door or gate can be open slightly or springs open automatically under the pressure of the sealing rubber and the restoring force of the preloaded rotary latch. Fingers or articles cannot become jammed between door and frame in the first place, or at least rapid opening of the door is ensured if such a misfortune has arisen. As already indicated, the closure device according to the invention is particularly suitable for doors, gates or hoods of motor vehicles, and a use with other doors, gates or flaps, for example in the field of construction engineering, is conceivable.
Preferably, the drive of the shutting aid acts on a first eccentric member which entrains the rotary latch on the last section of its travel into the closed position. Such a drive is of simple construction and permits the gear ratio to be selected within a wide range, this being determined, inter alia, by the lever ratios existing between the first eccentric member and its pivot and between the point of engagement of the eccentric member on the rotary latch and its pivot.
In order to permit closing of the rotary latch even when the eccentric member comes to a halt in the region of the shutting position as a result of a defective drive motor, the first eccentric member preferably acts on an intermediate piece which is mounted on the pivot of the rotary latch, entrains this into the closed position and can be twisted in the opposite direction against the load of a preloaded spring relative to the rotary latch. With such an embodiment, any blocked eccentric member merely blocks the intermediate piece, while the movable rotary latch permits an emergency closure of the door or gate.
In a particularly preferred embodiment of the closure device according to the invention, the first eccentric member is arranged on a multi-membered toggle lever which is retained in a basic position by a preloaded spring, in which position the necessary shutting forces can be transmitted to the rotary latch, and which can be moved by mechanical engagement into a bent-in position in which the first eccentric member moves out of its entraining position.
The interruption of the force flow via the bending-in of a toggle lever offers the advantage that the latter automatically returns to its basic position, as a result of the preloaded spring, after completion of the release action and the system is thus restored to its original state. Breaker couplings in the force flow are also conceivable, but involve the problem that, after release has taken place, there may in some cases no longer be a defined position of the eccentric member or of any other drive member relative to the shutting of the door and to the drive motor. Toggle levers also offer the possibility of influencing the actuating force necessary to bend in the toggle lever easily by varying the lever lengths and position of the joints, and varying the point of contact, the mechanical engagement preferably taking place at a point on the toggle lever at which only a slight force is necessary to bend in the toggle lever and a short displacement travel is sufficient to move the toggle lever beyond a dead-center position. As soon as the dead-center position is passed, the further bending-in of the toggle lever against the pre-stress of the preloaded spring is effected by the drive motor of the shutting aid. The eccentric member, as it moves aside, releases the rotary latch so that a blockage is ruled out.
The release mechanism is preferably so designed that is has a manually actuated and/or motor-actuated actuating lever which, in its open position, moves the ratchet out of the engagement with the rotary latch and bends in the toggle lever, in which case it can act directly on the toggle lever. With such a construction, the release mechanism can be kept very simple, it being preferable for the actuating lever to be mounted about a common pivot with the ratchet and the latter to be capable of being twisted relative to the actuating member by the exertion of pressure by the rotary latch against a preloaded spring. This last measure ensures that the toggle lever can be bent in only when the actuating lever is actuated, so that accidental releases are avoided.
Preferably, a motor-driven second eccentric member entrains the actuating member for release purposes, provision being made, in a particularly advantageous embodiment of the invention, for the two eccentric members to be driven by a common motor which is movable between two end positions of a gearing, the door closing in the region of one end position of the first eccentric member and the second eccentric member releasing the ratchet via the actuating member in the region of the other end position with a reversed direction of rotation of the motor. In this embodiment it is possible, at low cost and with only one drive motor, also to provide motor-driven release of the closure device, in which case of course a manual intervention, or automatic intervention independent of the joint drive motor, should be provided in order to interrupt the force flow which interrupts the force flow even before the joint drive motor acts on the actuating lever. In addition to eccentrically arranged bolts, cam disks, for example, are also conceivable as eccentric members. The first eccentric member for driving the shutting aid is stepped down because of the greater forces, in other words it rotates more slowly than the second eccentric member which is designed to release the closure device as quickly as possible.